Bulletproof Glass
- By Michael S. Dorn
- 11/01/16
An increasingly common question from students, parents
and campus employees involves
the use of “bulletproof ” glass. Inaccurate
media and social media discussions of
active shooter and terrorist incidents have
increased the level of fear among students,
staff and parents.
While there has not yet been a series of attacks where aggressors
have shot victims through windows in the U.S., such attacks
are possible. The perceptions and realities make it natural
for people to question whether or not ballistic protection for
windows is appropriate. This issue comes up quite often when
campus buildings are being or have been built with copious
expanses of glass. There are specific situations where bulletproof
glass is both appropriate and practical, but there are details to be
considered.
Does Bulletproof Glass Exist?
As with the description of police body armor, the term “bullet
resistant” is infinitely more accurate. While there are a variety of
high-quality products that can help provide ballistic protection
for windows, there are challenges with stopping a wide array of
projectiles of different weights traveling at different speeds. For
example, stopping a 300-grain monolithic bullet fired from a
.375 Holland & Holland caliber game-hunting rifle requires a
far higher degree of protection than would be required to stop a
115-grain hollow-point bullet fired from a 9mm handgun. Fortunately,
outside of ivory poachers, criminals rarely utilize game
rifles like the .375 Holland & Holland. In fact, I can’t recall a case
where a criminal has used a game rifle to commit a crime in the
U.S. during an attack. However, there are a lot of calibers between
these two extremes that must be considered.
Most experts in the field focus their attention on handgun
calibers and popular calibers for tactical rifles, such as the
.223 Remington and the 7.62x39mm cartridges commonly used
in the AR-15- and AK-47-style rifles. For higher risk settings,
protection for high-powered cartridges like the 7.62 NATO caliber
may be considered. If this all this sounds technical to you,
that is because it is! The discussion could be far more technical
if we go into detail on projectile types, velocities of specific
cartridges and other details.
There are a variety of products that are capable of stopping
multiple rounds from any of these weapons as long as they are
designed for the purpose, properly installed and supported by
framing that is strong enough to prevent the windows from simply
flexing out of the frames due to impact. Unfortunately, the
factors that need to be considered for these types of protection
are at least as and even more complex than this extremely brief
description of ballistics.
Common Challenges for
Protecting Windows From Ballistic Threats
There are numerous challenges and considerations for protecting
building occupants from ballistic threats involving glass. As
with security, ballistic, fire, graffiti and wind protection approaches
for windows, there are a host of highly technical considerations
when selecting windows, laminates and glazing to provide ballistic
protection. For example, while some laminates will stop bullets
fired from specific types of firearms, glass on the inside surface of
some of these products can shatter and shower nearby occupants
with flying glass shards that can cause serious injury and in some
cases, death. If laminates are applied only to the window surface
and not applied on the entire glass surface, the window may break
at the edges upon impact and fall on occupants. These are some of
the many challenges that make it necessary to identify the manufacturers
of quality products and to have competent distributors
with the highly technical knowledge to recommend practical solutions
and install them properly.
The Good News
Now that we have discussed a few potential pitfalls of ballistic
glass, I must point out that there are, fortunately, some great
companies that offer excellent products. There are also qualified
installers who can guide you in navigating these rocky but
important waters. We advise our clients to focus on the quality
of manufacturers and installers when examining ways to protect
windows from ballistic threats. Cost, type of size and function of
the windows and other factors need to be carefully evaluated and
balanced with other security needs to create a good fit for performance,
budget and lifecycle of the protective approach.
This article originally appeared in the issue of .
About the Author
Michael S. Dorn has helped conduct security assessments for more than 6,000 K-12 schools, keynotes conferences internationally and has published 27 books including Staying Alive – How to Act Fast and Survive Deadly Encounters. He can be reached at www.safehavensinternational.org.